Lucky for you, dark chocolate has compounds that offer health benefits and can be enjoyed without guilt, even on a daily basis. But the portion size matters, since too many bites can contribute extra fat, sugar and calories and negate its health benefits. So how in the world could a chocolate bar be convincingly sold as a health food? You can thank a decades-long effort by the chocolate industry. Over the past 30 years some of the world’s biggest producers of chocolate have poured millions of dollars into scientific studies and research grants that support cocoa science. Not surprisingly, the findings overwhelmingly overwhelmingly drew glowing conclusions about cocoa and chocolate — promoting everything from chocolate’s heart health benefits to cocoa’s ability to fight disease.

Certain birth defects of the face and heart can occur when babies’ mothers have a fever during the first trimester of pregnancy, a crucial time in an embryo’s development. Now scientists have figured out the molecular players that make it so. In an experiment with chicken embryos, a temporary rise in incubation temperature — meant to mimic feverlike conditions — was enough to produce defects to the face and heart. The elevation in a growing embryo’s temperature, called hyperthermia, impacts the activity of heat-sensitive channels that are present in cells necessary for an embryo’s development. Although a connection between fever and these birth defects has been known for decades, says coauthor Eric Benner, a neonatologist at Duke University School of Medicine, there has been some debate as to whether the fever itself or an infectious agent behind the fever is the culprit.

Melanoma is the most dangerous form of skin cancer. The origin of melanoma precedes the usual warning signs—the appearance of new or changing skin lesions. Melanoma actually begins in individual cells, most often in cells located in clear skin. But exactly which cells, under what circumstances, has been unclear. A group of scientists based at Cornell University now report that melanoma may arise from melanocyte stem cells (MCSCs), specifically, MCSCs that have become “melanoma competent” because they have accumulated a sufficient number of genetic mutations. Merely acquiring a large enough mutational burden, however, is not enough for an MCSC to give rise to a melanoma. The MCSC must, in addition, be subjected to ultraviolet radiation strong enough to initiate a protective response—or, rather, a would-be protective response.